When was Jesus born?At this time of year it is customary for certain scholars to debate just when Jesus was born, and whether it is right for us to celebrate His birth during this time of year at all. The long and the short of it is that no one knows for sure.
For example, detractors of a late-December date for the birth of Our Lord point out that shepherds would likely not be abiding in the fields during what is normally the rainy season of the year in Palestine. This is an excellent point, but even during the rainy season it is possible to have a day here and there where it didn’t rain, and shepherds in those days would have been tending to their flock on any night when it wasn’t raining.
Some critics say that the early Church did not celebrate the Nativity, because they did not know the date of Christ’s birth, but St. Justin Martyr was pretty adamant that in his day, Christians in most of the known world were celebrating the birth of Our Lord with annual rigor, though there was (and remains) a dispute within the Christian world as to whether the correct day to celebrate the Nativity is December 25 or January 6.
As many have pointed out, December 25 was also the solar feast Natalis Invicti, and not a few scholars believe that the date for the celebration of Christmas was borrowed from this very old pagan feast. It wouldn’t be the first time, nor the last time, that the Church “baptized” a holiday, and the theory is not far-fetched.
St. Ambrose and St. Jerome both say that in some form or other the census records of the Holy Family that would have been taken at Bethlehem still existed and could be found at Rome in their day. In our day, many records from the time of Augustus have been preserved, but others have been lost, and it is possible that these records were also lost. If true, however, access to these public records may explain why in the earliest martyrologies of the Church of Rome that list December 25 as the feast of the birth of Our Lord. The earliest known such martyrology, or list of martyrs and other historical events of the Church on a given day, dates all the way back to 205 AD. In it can be found:
"For the first coming of Our Lord in the flesh (in which He has been begotten), in Bethlehem, took place (25 December, the fourth day) in the reign of Augustus (the forty-second year, and) in the year 5500 (from Adam). And He suffered in His thirty-third year (25 March, the parasceve, in the eighteenth year of Tiberius Cæsar, during the consulate of Rufus and Rubellio).”
I happen to believe that the Lord was either born on what we now call Christmas Day or sometime very close to that date…but whatever day it was, it was the most important birthday in world history.